Quick question on final plug preparation

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#1

My plug is nearly ready to take a mould from, I’ve wet sanded with 800 grit, do I now go onto a finer grade? If so what is the next stage? Polish? What type?

#2

I don’t know either but I’m interested in the response

#3

Yes, i would go to 1000, then 1500 and finally 2000. Then compound and buff to a high gloss. Then treat the part with a sealer then a release. You are now ready to start your mold.

#4

I agree with the above.

I go right down to 2000 , then polish with a cutting compound…

http://www.cartersconsumables.co.uk/polish-compounds-farecla-polish-c-94_104_202.html

And then go over it with…
http://www.cartersconsumables.co.uk/3m80349-perfectit-extra-fine-material-polish-litr-p-1221.html

My release is TR wax.

End result…:smiley:

#5

Depends a bit on the part. Sometimes it is easier to sand and polish the mould.

In any case, a super high gloss mould gives less problems when demoulding, so always aim for that.

#6

I was always told “better mould prep is less work in the end”. So like Herman said regardless you should because it’ll be easier to take out later.

Your plug should be the same finish as you want your finished part to be. If you want your part to look like it was pulled out and sanded with 800 grit then leave it, but if you want your part to be smoother and shiner, then your plug should be also.

I guess though it depends on the part as well and what you plan on doing with it in the end…

#7

Would this be suitable? http://www.performancemotorcare.com/acatalog/info_PMC00177.html

#8

That Meguiars product will likely not have enough cutting action to polish out 2000 grit sanding marks. You will likely need to start will something more agressive like Meguiars M105, followed by M205. Thats what I use for automotive 2K paints and it works really well.

#9

So it’s universal to start around
800 (or lower depending on the surface conditions)
1000
1500
2000
Polish

Any recommended polishes for tooling gelcoats in the US?

#10

I forgot to mention I’ve used a 2k primer filler as the top surface, will this polish up ok or do I need to paint with something else first?

Thanks for the advice so far!

#11

It should buff out. When looking for compounds, you need to match your final wetsand to the first compound used. So if you finish with 1500, you need to find something in that range, generally automotive compounds start at 1200-2000. If you finish with trizact 3000 or 4000, that same compound will scratch deeper than your final sand. Obviously, your buffing pads need to correspond to the sytem you use.

#12

" 2k primer filler as the top surface, will this polish up ok or do I need to paint with something else first?"

I would use a 2k clear coat on top then sand and buff the clear you will get a harder surface for release with a qood gloss finish. Do a test piece.